[libvirt] [PATCH 33/26] snapshot: support extra state in snapshots

In order to distinguish disk snapshots from system checkpoints, a new state value that is only valid for snapshots is helpful. * include/libvirt/libvirt.h.in (VIR_DOMAIN_LAST): New placeholder. * src/conf/domain_conf.h (virDomainSnapshotState): New enum mapping. * src/conf/domain_conf.c (virDomainState): Use placeholder. (virDomainSnapshotState): Extend mapping by one for use in snapshot. (virDomainSnapshotDefParseString, virDomainSnapshotDefFormat): Handle new state. (virDomainObjSetState, virDomainStateReasonToString) (virDomainStateReasonFromString): Avoid compiler warnings. * tools/virsh.c (vshDomainState, vshDomainStateReasonToString): Likewise. (cmdList): Translate state output. * src/libvirt_private.syms (domain_conf.h): Export new functions. * docs/schemas/domainsnapshot.rng: Tighten state definition. * docs/formatsnapshot.html.in: Document it. * tests/domainsnapshotxml2xmlout/disk_snapshot.xml: New test. --- docs/formatsnapshot.html.in | 82 +++++++++++++++++++--- docs/schemas/domainsnapshot.rng | 15 ++++- include/libvirt/libvirt.h.in | 14 ++++- src/conf/domain_conf.c | 26 +++++-- src/conf/domain_conf.h | 3 +- src/libvirt_private.syms | 2 + tests/domainsnapshotxml2xmlout/disk_snapshot.xml | 35 +++++++++ tools/virsh.c | 10 ++- 8 files changed, 165 insertions(+), 22 deletions(-) create mode 100644 tests/domainsnapshotxml2xmlout/disk_snapshot.xml diff --git a/docs/formatsnapshot.html.in b/docs/formatsnapshot.html.in index edf20e8..21c83a0 100644 --- a/docs/formatsnapshot.html.in +++ b/docs/formatsnapshot.html.in @@ -7,6 +7,61 @@ <h2><a name="SnapshotAttributes">Snapshot XML</a></h2> <p> + There are several types of snapshots: + </p> + <dl> + <dt>disk snapshot</dt> + <dd>Contents of disks (whether a subset or all disks associated + with the domain) are saved at a given point of time, and can + be restored back to that state. On a running guest, a disk + snapshot is likely to be only crash-consistent rather than + clean (that is, it represents the state of the disk on a + sudden power outage, and may need fsck or journal replays to + be made consistent); on an inactive guest, a disk snapshot is + clean if the disks were clean when the guest was last shut + down.</dd> + <dt>VM state</dt> + <dd>Tracks only the state of RAM and all other resources in use + by the VM. If the disks are unmodified between the time a VM + state snapshot is taken and restored, then the guest will + resume in a consistent state; but if the disks are modified + externally in the meantime, this is likely to lead to data + corruption.</dd> + <dt>system checkpoint</dt> + <dd>A combination of disk snapshots for all disks as well as VM + state, which can be used to resume the guest from where it + left off with symptoms similar to hibernation (that is, TCP + connections in the guest may have timed out, but no files or + processes are lost).</dd> + </dl> + + <p> + Libvirt can manage all three types of snapshots. For now, VM + state snapshots are created only by + the <code>virDomainSave()</code>, <code>virDomainSaveFlags</code>, + and <code>virDomainManagedSave()</code> functions, and restored + via the <code>virDomainRestore()</code>, + <code>virDomainRestoreFlags()</code>, <code>virDomainCreate()</code>, + and <code>virDomainCreateWithFlags()</code> functions (as well + as via domain autostart). With managed snapshots, libvirt + tracks all information internally; with save images, the user + tracks the snapshot file, but libvirt provides functions such + as <code>virDomainSaveImageGetXMLDesc()</code> to work with + those files. + </p> + <p>System checkpoints are created + by <code>virDomainSnapshotCreateXML()</code> with no flags, and + disk snapshots are created by the same function with + the <code>VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY</code> flag; in + both cases, they are restored by + the <code>virDomainRevertToSnapshot()</code> function. For + these types of snapshots, libvirt tracks each snapshot as a + separate <code>virDomainSnapshotPtr</code> object, and maintains + a tree relationship of which snapshots descended from an earlier + point in time. + </p> + + <p> Attributes of libvirt snapshots are stored as child elements of the <code>domainsnapshot</code> element. At snapshot creation time, only the <code>name</code> and <code>description</code> @@ -21,9 +76,10 @@ <dl> <dt><code>name</code></dt> <dd>The name for this snapshot. If the name is specified when - initially creating the snapshot, then the snapshot will have - that particular name. If the name is omitted when initially - creating the snapshot, then libvirt will make up a name for the snapshot. + initially creating the snapshot, then the snapshot will have + that particular name. If the name is omitted when initially + creating the snapshot, then libvirt will make up a name for the + snapshot, based on the time when it was created. </dd> <dt><code>description</code></dt> <dd>A human-readable description of the snapshot. If the @@ -35,15 +91,21 @@ in seconds since the Epoch, UTC (i.e. Unix time). Readonly. </dd> <dt><code>state</code></dt> - <dd>The state of the domain at the time this snapshot was - taken. When the domain is reverted to this snapshot, the domain's state - will be set to whatever is in this field. Readonly. + <dd>The state of the domain at the time this snapshot was taken. + If the snapshot was created as a system checkpoint, then this + is the state of the domain at that time; when the domain is + reverted to this snapshot, the domain's state will default to + whatever is in this field unless additional flags are passed + to <code>virDomainRevertToSnapshot()</code>. Additionally, + this field can be the value "disk-snapshot" when it represents + only a disk snapshot (no VM state), and reverting to this + snapshot will default to an inactive guest. Readonly. </dd> <dt><code>parent</code></dt> - <dd>The parent of this snapshot. This element contains exactly - one child element, name. This specifies the name of the parent - snapshot of this snapshot, and is used to represent trees of - snapshots. Readonly. + <dd>The parent of this snapshot. If present, this element + contains exactly one child element, name. This specifies the + name of the parent snapshot of this snapshot, and is used to + represent trees of snapshots. Readonly. </dd> <dt><code>domain</code></dt> <dd>The domain that this snapshot was taken against. Older diff --git a/docs/schemas/domainsnapshot.rng b/docs/schemas/domainsnapshot.rng index a16d731..130dad9 100644 --- a/docs/schemas/domainsnapshot.rng +++ b/docs/schemas/domainsnapshot.rng @@ -22,7 +22,7 @@ </optional> <optional> <element name='state'> - <text/> + <ref name='state'/> </element> </optional> <optional> @@ -59,4 +59,17 @@ </element> </define> + <define name='state'> + <choice> + <value>nostate</value> + <value>running</value> + <value>blocked</value> + <value>paused</value> + <value>shutdown</value> + <value>shutoff</value> + <value>crashed</value> + <value>disk-snapshot</value> + </choice> + </define> + </grammar> diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in index e07dc20..c62577d 100644 --- a/include/libvirt/libvirt.h.in +++ b/include/libvirt/libvirt.h.in @@ -86,7 +86,14 @@ typedef enum { VIR_DOMAIN_PAUSED = 3, /* the domain is paused by user */ VIR_DOMAIN_SHUTDOWN= 4, /* the domain is being shut down */ VIR_DOMAIN_SHUTOFF = 5, /* the domain is shut off */ - VIR_DOMAIN_CRASHED = 6 /* the domain is crashed */ + VIR_DOMAIN_CRASHED = 6, /* the domain is crashed */ + + /* + * NB: this enum value will increase over time as new events are + * added to the libvirt API. It reflects the last state supported + * by this version of the libvirt API. + */ + VIR_DOMAIN_LAST } virDomainState; typedef enum { @@ -1893,6 +1900,11 @@ typedef enum { VIR_KEYCODE_SET_USB = 7, VIR_KEYCODE_SET_WIN32 = 8, + /* + * NB: this enum value will increase over time as new events are + * added to the libvirt API. It reflects the last keycode set supported + * by this version of the libvirt API. + */ VIR_KEYCODE_SET_LAST, } virKeycodeSet; diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 5903f65..d5784e1 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -420,7 +420,7 @@ VIR_ENUM_IMPL(virDomainHostdevSubsys, VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_LAST, "usb", "pci") -VIR_ENUM_IMPL(virDomainState, VIR_DOMAIN_CRASHED+1, +VIR_ENUM_IMPL(virDomainState, VIR_DOMAIN_LAST, "nostate", "running", "blocked", @@ -429,6 +429,17 @@ VIR_ENUM_IMPL(virDomainState, VIR_DOMAIN_CRASHED+1, "shutoff", "crashed") +/* virDomainSnapshotState is really virDomainState plus one extra state */ +VIR_ENUM_IMPL(virDomainSnapshotState, VIR_DOMAIN_LAST+1, + "nostate", + "running", + "blocked", + "paused", + "shutdown", + "shutoff", + "crashed", + "disk-snapshot") + #define VIR_DOMAIN_NOSTATE_LAST (VIR_DOMAIN_NOSTATE_UNKNOWN + 1) VIR_ENUM_IMPL(virDomainNostateReason, VIR_DOMAIN_NOSTATE_LAST, "unknown") @@ -11052,7 +11063,7 @@ virDomainSnapshotDefParseString(const char *xmlStr, _("missing state from existing snapshot")); goto cleanup; } - def->state = virDomainStateTypeFromString(state); + def->state = virDomainSnapshotStateTypeFromString(state); if (def->state < 0) { virDomainReportError(VIR_ERR_INTERNAL_ERROR, _("Invalid state '%s' in domain snapshot XML"), @@ -11120,7 +11131,7 @@ char *virDomainSnapshotDefFormat(char *domain_uuid, virBufferAsprintf(&buf, " <description>%s</description>\n", def->description); virBufferAsprintf(&buf, " <state>%s</state>\n", - virDomainStateTypeToString(def->state)); + virDomainSnapshotStateTypeToString(def->state)); if (def->parent) { virBufferAddLit(&buf, " <parent>\n"); virBufferAsprintf(&buf, " <name>%s</name>\n", def->parent); @@ -11712,6 +11723,7 @@ virDomainObjSetState(virDomainObjPtr dom, virDomainState state, int reason) case VIR_DOMAIN_SHUTDOWN: last = VIR_DOMAIN_SHUTDOWN_LAST; break; case VIR_DOMAIN_SHUTOFF: last = VIR_DOMAIN_SHUTOFF_LAST; break; case VIR_DOMAIN_CRASHED: last = VIR_DOMAIN_CRASHED_LAST; break; + default: last = -1; } if (last < 0) { @@ -11745,9 +11757,9 @@ virDomainStateReasonToString(virDomainState state, int reason) return virDomainShutoffReasonTypeToString(reason); case VIR_DOMAIN_CRASHED: return virDomainCrashedReasonTypeToString(reason); + default: + return NULL; } - - return NULL; } @@ -11769,9 +11781,9 @@ virDomainStateReasonFromString(virDomainState state, const char *reason) return virDomainShutoffReasonTypeFromString(reason); case VIR_DOMAIN_CRASHED: return virDomainCrashedReasonTypeFromString(reason); + default: + return -1; } - - return -1; } diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 7dbf353..863d64f 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -1312,7 +1312,7 @@ struct _virDomainSnapshotDef { char *description; char *parent; long long creationTime; /* in seconds */ - int state; + int state; /* enum virDomainSnapshotState */ virDomainDefPtr dom; /* Internal use. */ @@ -1739,6 +1739,7 @@ VIR_ENUM_DECL(virDomainGraphicsSpicePlaybackCompression) VIR_ENUM_DECL(virDomainGraphicsSpiceStreamingMode) VIR_ENUM_DECL(virDomainGraphicsSpiceClipboardCopypaste) VIR_ENUM_DECL(virDomainNumatuneMemMode) +VIR_ENUM_DECL(virDomainSnapshotState) /* from libvirt.h */ VIR_ENUM_DECL(virDomainState) VIR_ENUM_DECL(virDomainNostateReason) diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index 9530567..034443c 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -392,6 +392,8 @@ virDomainSnapshotHasChildren; virDomainSnapshotObjListGetNames; virDomainSnapshotObjListNum; virDomainSnapshotObjListRemove; +virDomainSnapshotStateTypeFromString; +virDomainSnapshotStateTypeToString; virDomainSoundDefFree; virDomainSoundModelTypeFromString; virDomainSoundModelTypeToString; diff --git a/tests/domainsnapshotxml2xmlout/disk_snapshot.xml b/tests/domainsnapshotxml2xmlout/disk_snapshot.xml new file mode 100644 index 0000000..391bb57 --- /dev/null +++ b/tests/domainsnapshotxml2xmlout/disk_snapshot.xml @@ -0,0 +1,35 @@ +<domainsnapshot> + <name>my snap name</name> + <description>!@#$%^</description> + <parent> + <name>earlier_snap</name> + </parent> + <state>disk-snapshot</state> + <creationTime>1272917631</creationTime> +<domain type='qemu'> + <name>QEMUGuest1</name> + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid> + <memory>219100</memory> + <currentMemory>219100</currentMemory> + <vcpu cpuset='1-4,8-20,525'>1</vcpu> + <os> + <type arch='i686' machine='pc'>hvm</type> + <boot dev='hd'/> + </os> + <clock offset='utc'/> + <on_poweroff>destroy</on_poweroff> + <on_reboot>restart</on_reboot> + <on_crash>destroy</on_crash> + <devices> + <emulator>/usr/bin/qemu</emulator> + <disk type='block' device='disk'> + <source dev='/dev/HostVG/QEMUGuest1'/> + <target dev='hda' bus='ide'/> + <address type='drive' controller='0' bus='0' unit='0'/> + </disk> + <controller type='ide' index='0'/> + <memballoon model='virtio'/> + </devices> +</domain> + <active>1</active> +</domainsnapshot> diff --git a/tools/virsh.c b/tools/virsh.c index 49ce814..27d0d6f 100644 --- a/tools/virsh.c +++ b/tools/virsh.c @@ -920,7 +920,7 @@ cmdList(vshControl *ctl, const vshCmd *cmd ATTRIBUTE_UNUSED) vshPrint(ctl, "%3d %-20s %s\n", virDomainGetID(dom), virDomainGetName(dom), - vshDomainStateToString(vshDomainState(ctl, dom, NULL))); + _(vshDomainStateToString(vshDomainState(ctl, dom, NULL)))); virDomainFree(dom); } for (i = 0; i < maxname; i++) { @@ -935,7 +935,7 @@ cmdList(vshControl *ctl, const vshCmd *cmd ATTRIBUTE_UNUSED) vshPrint(ctl, "%3s %-20s %s\n", "-", names[i], - vshDomainStateToString(vshDomainState(ctl, dom, NULL))); + _(vshDomainStateToString(vshDomainState(ctl, dom, NULL)))); virDomainFree(dom); VIR_FREE(names[i]); @@ -14521,6 +14521,8 @@ vshDomainState(vshControl *ctl, virDomainPtr dom, int *reason) static const char * vshDomainStateToString(int state) { + /* Can't use virDomainStateTypeToString, because we want to mark + * strings for translation. */ switch ((virDomainState) state) { case VIR_DOMAIN_RUNNING: return N_("running"); @@ -14535,6 +14537,7 @@ vshDomainStateToString(int state) case VIR_DOMAIN_CRASHED: return N_("crashed"); case VIR_DOMAIN_NOSTATE: + default: ;/*FALLTHROUGH*/ } return N_("no state"); /* = dom0 state */ @@ -14636,6 +14639,9 @@ vshDomainStateReasonToString(int state, int reason) ; } break; + + default: + ; } return N_("unknown"); -- 1.7.4.4